When Marc Ross ran through recent pollution data for cars last month, he was shocked. So-called high-emitters - cars whose air-pollution controls often failed after a few years - had virtually disappeared. Cars are polluting less, apparently, because they're better made.
"It's preliminary," says Mr. Ross, a University of Michigan physicist and auto-emissions researcher. But "the story is much better than we expected."
It's not just emission systems that are undergoing a quality revolution. Quietly, manufacturers are turning out everything from car-engine parts to plumbing fixtures that are better made than a decade ago. A major reason is precision. Using computer-controlled machinery, manufacturers are making parts that are virtually alike. There's far less than a hair's-breadth of difference between the first piece that rolls off the assembly line and the 10,000th.
"We used to talk about 1/1,000th of an inch," says Jim Lorincz, editor of Tool Production magazine in Solon, Ohio. "Now, we are talking in terms of 1/10,000th of an inch and even millionths."
Some machine-tool makers (the folks who make the machines that make other machines) are beginning to sound like computer-chip makers.
"We're well under one micron," says Gary Roeder, an operations vice president with Landis Gardner, which makes machines that create fuel injectors. Five years ago, the Waynesboro, Pa., company was making machines only accurate to within 2.5 microns. (A micron is extremely small. It takes 1,000 microns to equal 1 millimeter; it takes 70 to equal the width of an average human hair.)
We all benefit from more precision although we rarely see those benefits. Pieces fit together better. Machines turn faster. Engines operate more predictably. Such consistency allows carmakers to incorporate sensors and other sophisticated technologies to fine-tune their engines. The results are dramatic. The engines in today's American cars are, on average, 40 percent smaller than their 1975 counterparts. But they're 14 percent more powerful, according to the US Environmental Protection Agency, and twice as fuel efficient.
Of course, more precision isn't the only factor. Lighter materials, computer technologies, and better designed engines have all played major roles in creating a better car. Most people are familiar with the precision movement because of computer chips. That industry is moving to technology that can etch 0.25 micron channels in silicon. The surprise is that less high-tech industries are also taking up the precision gauntlet.
Like plumbing fixtures. For the past four years, the US has required bathroom-fixture companies to sell residential toilets that use no more than 1.6 gallons of water per flush. These new water-saving toilets usually work fine when attached to high-pressure plumbing systems.
When the pressure is low, however, some of them don't always work so well. They can't.... that is to say they don't ... er ... fully evacuate the fixture. (Don't you love industry lingo!)
That's why Sloan Valve Co. has improved its manufacturing precision to within 3/1,000th of an inch. The company says its more accurate valve can deliver enough water at the precise moment to do its duty, even in low-pressure situations.
"If we didn't have tight tolerances on machining, we'd deliver too much or too little," says Fred Hawley, national sales manager for Sloan.
And that can be disastrous in a bathroom fixture - or in a car.
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